// 使用帮助函数_average重构averageDollarValue，使用函数组合的方式实现
// let _average = function (xs) {
//     return fp.reduce(fp.add, 0, xs) / xs.length
// }// 无需改动

// let averageDollarValue = function(cars){
//     let dollar_values = fp.map(function(car){
//         return car.dollar_value
//     },cars)
//     return _average(dollar_values)
// }

const cars = [
    {name:'Ferrair FF',horsepower:660,dollar_value:700000,in_stock:true},
    {name:'Spyker C12 Zagato',horsepower:650,dollar_value:648000,in_stock:false},
    {name:'Jafuar XKR-S',horsepower:550,dollar_value:132000,in_stock:false},
    {name:'Audi R8',horsepower:525,dollar_value:114200,in_stock:false},
    {name:'Aston Martin One-77',horsepower:750,dollar_value:1850000,in_stock:true},
    {name:'Pagani Huayra',horsepower:700,dollar_value:1300000,in_stock:false}
]
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length
}
const fp = require('lodash/fp');
const f3 = car => car.dollar_value;
const f4 = fp.flowRight(_average, fp.map(f3))

console.log(f4(cars));
